Multistage Leaching Kinetics of Chromite in HCl-Na2CrO4 System
The multi-stage leaching of chromite in HCl-Na2 CrO4 system has been studied,and the leaching kinetics of main metal elements in chromite has been discussed.The results show that under the optimal conditions of particle size of 45～75 μm,oxidizing agent Na2CrO4 dosage of 0.6 times of theoretical dosage,reaction time of 5 h,reaction temperature of 453.15 K,ball to material mass ratio of 1/1,stirring speed of 30 r/min,liquid volume to solid mass ratio of 4 mL/1 g,the three-stage cyclic leaching is carried out,the leaching rates of Cr,Fe,Al and Mg can reach 91.98％,94.54％,76.62％and 78.03％,respectively.The acid leaching reaction of chromite is controlled by interfacial chemical reaction.The apparent activation energies of Cr,Fe,Al and Mg are 45.80,40.43,42.08 and 43.54 kJ/mol,respectively.In the range of 373.15～473.15 K,and the leaching effect is good.
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